Telephone-exchange.



N. E. NORSTROM. I TELEPHONE EXCHANGE. APPLIOATION FILED PER-23, 1909.

980,883. Patented Jan. 3, 1911.

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N. E. NORSTROM. TELEPHONE EXGHANGE. APPLICATION FILED FEB. 23, 1909. 980,883. Patented Jan.3, 1911.

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UNITED STATES PATENT OFFICE.

NILS EMEL NORSTROM, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE ANDERSON ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OF KANSAS.

TELEPHONE-EXCHANGE.

Specification of Letters Patent.

Patented Jan. 3, 1911.

Application filed February 23, 1909. Serial No. 479,445.

To all whom it may concern:

Be it known that I, NILs Farm. NORSTROM, a citizen of the United States of America, and a resident of Chicago, county of Cook, and State of Illinois, have invented certain new and useful Improvements in Telephone- Exchanges, of which the following is a specification.

My invention relates to telephone exchanges, and has for its object improvements therein.

In the accompanying drawingsFigure 1 is a front elevation of a calling device to be used at a central ofiice in connection with party lines; Fig. 2 is a section on line 2-2 of Fig. 1; Fig. 3 is a front elevation similar to Fig. 1, but with the front cover removed; Fig. at is a section on lines 4-l of Figs. 1 and 3; Fig. 5 is a section on line 5-5 of Fig. 3, with some parts omitted so that other parts may be more easily seen; Fig. 6 is a section on line 66 of Fig. 3 with other parts omitted; Fig. 7 is a section on the broken line 7-7 of Fig. 1; Fig. 8 is an enlarged detail of devices for opening and closing circuits at certain times, and Fig. 9 is a diagram of the circuits in the device and in the central oflice associated with the device.

Supported in the casing A is a shaft B, one portion of which consists of a long pinion B Secured to the shaft B is a spring B which normally holds said shaft and the connecting parts in the position shown in the drawings. Engaging one end of the pinion B is a rack B the lower end of which is attached to a piston working in the cylinder B In this cylinder is a liquid through which the piston has to pass in being raised or lowered by a movement of the shaft B. The object of this piston, cylinder and contained liquid is to prevent the spring B returning the shaft B and connected parts too rapidly to normal position when moved therefrom and released as will be hereinafter described. To permit a free and easy raising of the piston it may contain a valve opening downward. Loosely mounted on an adjacent shaft C are a series of levers O, each of which carries a sector of a gear O normally out of connection with the pinion B but adapted to engage that pinion and turn the shaft B when such lever O is de pressed. Secured to each lever O adjacent to its gear C is a hub C having V-shaped notches C on opposite sides, which notches are normally engaged by insulating rollers C supported on adjacent springs as shown in Fig. 6. These springs are contact springs which make electrical connection with other contact springs as will be -hereinafter described. VVhen the lever C is in its elevated position the rollers O are pressed by their supporting springs into the notches O and this pressure acts to hold the lever in position with its gear teeth O clear of the pinion B Then the lever is depressed by hand, the consequent movement of the notches C from the rollers O spreads these rollers and their supporting springs so as to change the electrical connections before mentioned.

On the back of each lever O is a lug O" which is adjacent to or touches a bail 0' supported from the top of the casing A, when the said lever is in normal position. If the lever is pushed backward the bail C is caused to swing on its pivoting supports. On the bail O is a piece of insulation C Adjacent to this insulation is a contact spring as shown at the top of Fig. 5, which contact spring has its electrical connections changed, as will be hereinafter described, each time the bail swings on its pivot as the result of pushing any one of the levers O backward.

Secured on one end of the shaft O is an arm D having a pin D extending from opposite sides thereof. Loosely mounted on the shaft O at one side of the arm D is another arm D adapted to engage and press outward an insulating roller D supported on an adjacent spring 34. On the arm D is a pin D adapted to be engaged by the pin D on the arm D, so that a movement of the arm D will move the arm D successively in opposite directions by striking the pin D on opposite sides. Loosely mounted on the shaft O at the other side of the arm D is a third arm D adapted to be engaged by the pin D in the same way. The arm D is adapted to engage an insulating roller D and push it outward a short distance. The arm D is adapted to engage the same roller and push it outward farther than does arm D. The rollers D and D are on contact springs 3e and 3 which are located adjacent to other springs, as shown in Figs. 4 and 9. Pushing these rollars outward is for the purpose of changing the electrical connections of these springs as will be hereinafter described. Secured to the shaft O adjacent to these arms is a serrated wheel E which engages an insulating roller E on a spring arm E the movement of which changes the electrical connections of adjacent springs as will be hereinafter described. Secured to the other end of the shaft C is an arm H which carries a brush H adapted to complete electrical connection between a metallic ring H and a series of contact points H supported in an insulating ring H secured to a partition A in the casing A.

Supported to slide on guide screws K is a metallic plate K, (Figs. (3 and 9) and in this plate are a series of holes 1' In the front plate of the casing A, opposite each hole K is a key K connected by wire to a contact point H. These keys K are numbered or otherwise marked to indicate different stations on the party lines with which the calling device is associated. These keys are normally held in the position shown in Fig. 6 by springs located within the bosses K, but may be pushed inward by hand so that they will engage and pass through the holes I in plate K. Each key has its stem pointed and grooved as shown at K in Fig. 9. The plate K is held by a spring K so that the holes K do not register exactly with the stems of K, but by pressing a key inward the plate is moved slightly on its guides against the action of the spring K, and when the pointed head has passed through, the spring moves the plate to catch and hold the key in its depressed condition. If, at the time of depressing a key, any other key is being held depressed, the movement of the plate to per mit the pointed stem of key being depressed to pass through will release this other key. As a consequence, only one key is in a depressed condition at any one time. Two or more may, however, be depressed at the same time provided that they are pushed inward simultaneously.

ASSOCiatQtl with the apparatus so far described is a polarized magnet M whose armature M is movable in only one direction from its normal position as shown in Fig. 9. When impulses flow through the magnet M in one direction the armature M vibrates rapidly, but when the impulses flow in the other direction the armature is simply pressed more firmly against its back stop M Also associated with the apparatus a battery X, an alternating generator G, and an operators set S.

The operation may be described as follows, special reference being made to Fig. 9 for matters involving electrical conned tions. Assuming a call received at the central oflice from a party on a party line who wishes to talk with another party on the same line, the ope 'ator inserts the plug which is associated with some particular lever C in the jack of the line calling. The tip and sleeve of this plug are represented by the contacts 16 and 17 of Fig. 9. By pressing her listening key P, her set is in connection with the calling line. Upon being informed of the station wanted, the operator presses the key K representing this station, pulls down the lever C associated with the plug and cord used and then permits the lever to be returned to normal position under the action of the spring B She follows this by pressing the lever backward for a brief period, and then permits it to resume normal position. In moving a lever C and a hub C from normal position the rollers C are spread and the springs 15 and 18 are moved from connection to the adjacent inner to the adjacent outer springs. Also the arm D is moved away from the roller D permitting spring 3 to engage spring 2, and the ser'ated disk E vibrates the arm E so as to make the springs carried thereby connect alternately to the springs between which they are located. At each inward vibration of E a current flows from battery X-1-2 3 --5G7 -S91O 1112131416 over the party line and through the apparatus at each station and back17--1819 2021-22 23 2 125-26--2728X. Impulses in this direction are called release impulses.

impulses flow in corresponding directions through M, the magnet being operated by those in one direction only. hen the magnet is operated its armature M vibrates rapidly making and breaking connections between M and M As this point is in the circuit with the party line. such making and breaking of this connection breaks up the comparatively long impulses resulting from contacts made by the springs 11 and 23. \Vhen the roller D is in its normal or inner position it is the impulses known as operating impulses that are thus broken up. hen the roller D is moved outward so that spring 34 is shifted from spring 35 to spring 30, the connections are reversed so that it is the release impulses that are broken up. After the lever C has been moved about four-fifths of its entire downward movement, the pin D on the arm D strikes the other side of the arm D and moves it under and past the roller D. This affects nothing at this time as the apparatus at the local stations has not yet been operated. Just as the downward movement of the lever C is being finished the pin D.

strikes the other side of pin D and moves D under roller D so as to hold that roller out and change the connections of the adjacent springs, which connections reverse the connections of the magnet M with respect to the operating and releasing impulses. The consequence is that as the apparatus returns to normal position sending out impulses alternately in opposite directions as before, it is the releasing impulses which are broken up by the magnet M, the operating impulses being complete and serving to operate the apparatus at the several local stations. During the sending of these impulses the brush H is moving over the contacts H* in ring H When this brush reaches the contact which is connected to the depressed key K there is a shunt from 7 to 10 which excludes the contact M as follow: TlOH HH*llK K Kl210. This occurs in one of the release impulses which are being broken up into very short impulses by the vibration of the armature M The result is that this particular release impulse, which is for a particular station, is not broken up like other release impulses but goes over the party line as one complete impulse to cause an operation at the selected station which would not be performed by broken im pulses. If two or more keys K are simultaneously depressed, then the same thing happens for each corresponding station. When the moved lever C is about fourfifths of the way back to normal position and after all of the operations so far described have been performed the pin D again strikes the arm D" and returns it to normal position as shown in Fig. 4-. The outer face of the arm D is wide and holds the spring 3 away from spring 2 and against the spring 45 for an appreciable length of time, or during a time in which five or six or more impulses of the kind previously described would be sent over the party line. This changing of the connections for the contact spring 3 cuts out the battery X and cuts in the generator G. A ringing current then flows: G43l4 4534 and over the previously described course to 27G. This automatically sig nals the selected station, the signaling op-- eration stopping by the arm passing the roller D just as the apparatus reaches its normal position. Further signaling of the called station is accomplished by pressing the lever G backward to connect spring 6 to 46. The current flows G4C3 l6-6 and over the same line as before.

It will be observed that the apparatus has been arranged so that practically everything necessary in the calling operation is performed automatically as the result of depressing a lever C. Thus, the first movement of the lever turns the hub C which connects a desired cord and plug to the contact devices for sending impulses over the line. The same movement also winds the spring B which spring subsequently drives the apparatus to send out operating im pulses over the line. The movement down- *ard also sends out releasing impulses, and the terminal part of the movement downward shifts the connections for the impulses sent so that on the automatic return the impulses automatically sent are of the operating kind. And further, the same lever by means of its projection C serves as a means to connect the ring back if the automatic ringing is not sufficient to call the subscriber. Releasing without operating is accomplished by moving the lever a short distance from normal, but not enough to move the parts D D etc. In fact, this one and comparatively simple lever is made to perform the functions of several pieces formerly operated in succession by the operator.

hat I claim is 1. The combination with a device arranged to send impulses alternately in opposite directions over a party line, and means for breaking the impulses in one of said directions up into very short impulses, of automatically operating means for preventing selected ones of such impulses from being so broken. up.

2. The combination with a device for sending impulses alternately in opposite directions over a party line, and means for breaking up the impulses in one of said directions into very short impulses, of a series of keys representing different stations on the line over which impulses are to be sent, and automatically operating means for preventing the breaking up of the impulses which cor respond to actuated keys.

3. The combination with a device for sending a series of impulses over a line, and means for breaking up alternate impulses into very short impulses, of a series of keys representing alternate impulses sent by said device, and circuit connections operated by the actuation of the keys and so arranged that each impulse corresponding to an actuated key will pass by the impulse breaking means and thereby remain unbroken.

l. The combination with a device adapted to be moved by hand from its normal position and to be automatically returned to its normal position, contacts operated by such movements so as -to send impulses alternately in opposite directions over a line, and means by which the impulses in one of said directions are broken up into a series of very short impulses, of electrical connections shifted by the terminal part of the movements of said device from and to normal position so arranged that the impulses in one direction will be broken when the device is moving from normal and the impulses in the other direction will be broken when the device moving toward normal.

The combination with a device adapted to be moved successively in opposite directions and to send alternating impulses during both movements, of automatically operating means for breaking the impulses in one direction when said device is moving in one direction and for breaking the impulses in the other direction when the device is moving in the other direction.

6. The combination with a device for sending impulses over a line, and automatic means for breaking up alternate impulses into very short impulses, of a normally open shunt around said automatic means, and devices tor closing the shunt for desired ones of the impulses normally broken by said automatic means.

7. In the calling device, a lever arranged to wind the device and to select a cord when moved, automatically operating means for returning the lever to normal position after being moved and for sending operating and signaling impulses during such return movement, and connections by which a secondary movement of said lever serves to cause the sending of additional signaling impulses.

8. In a calling device, a shaft, by the movement of which the device is operated, an. impulse sending device operated by the movement of said shaft, a circuit changing device also operated by the movement of said shaft, and means for automatically shunting a desired one of the impulses sent while said shaft is moving.

9. In a calling device, a shaft having a pinion thereon, a series of gears independently movable and each disengaged from said pinion but adapted to engage the same when moved, and impulse sending devices connected to and operated by said shaft.

10. The combination with a party line, a battery, a contact making device by which impulses are sent from the battery over the line, and circuit shifting devices by means of which such impulses become releasing,

operating and signaling impulses in succession, of a series of levers, and automatically operating means by which upon a movement of any one of said levers from and to its normal position the several devices will be operated in the proper succession to place a desired station in telephonic connection with the party line and signal such station.

11. The combination with devices for sending a series of impulses in succession, of automatically operating means for shunting any desired one of the impulses in said series.

Signed at Chicago, Ill., this 18th day of Feb. 1909.

NILS EMEL NORSTROM. lVitnesses C. L. RnDrmLn, CARRIE E. JORDAN. 

